Illinois’ attorney general on Monday asked the state’s highest court to review what prosecutors consider to be too lenient a sentence for the white Chicago police officer who fatally shot black teenager Laquan McDonald.

Jason Van Dyke, 40, was sentenced last month to six years and nine months in prison for second-degree murder for shooting McDonald in 2014 in a landmark case that highlighted tensions over racism in the United States‘ third-largest city.

Attorney General Kwame Raoul and the special prosecutor who won the conviction against Van Dyke said they believe Judge Vincent Gaughan did not properly apply the law when he sentenced the former police officer.

Because Illinois allows some murder convicts to serve only half of their sentences, Van Dyke, who has already served several months, may only need to serve three years in prison.

In a rare move, Raoul and Kane County State’s Attorney Joseph McMahon filed a request with the Illinois Supreme Court seeking an order that would send the case back to Gaughan for a new sentence.

Van Dyke could appeal the petition, they said.

“This is a question of the law,” Raoul said.

“And it is in the interest of justice that the law be followed no matter who the defendant and no matter who the victim is in a particular case.”

Lenient sentence

Van Dyke fatally shot McDonald on October 20, 2014, after responding to a call about a teenager breaking into vehicles in a trucking yard.

Other officers back Van Dyke’s claim that McDonald, who had a small knife with its blade folded, posed a threat to Van Dyke’s life.

Van Dyke then fired 16 shots at McDonald on October 20, 2014, including after the 17-year-old’s body hit the ground.

Country-wide outrage and protests followed the release of a police dashboard camera video showing McDonald being repeatedly shot, compelled by a Freedom of Information Act lawsuit more than a year after the shooting.

The ensuing firestorm over the case prompted the dismissal of the city’s police superintendent and calls for Chicago Mayor Rahm Emanuel to resign.

Emanuel is not seeking a third term in this month’s mayoral election.

Following the ruling last month, activists decried the sentence as too lenient, while Van Dyke’s lawyer said his client “felt great”.

Van Dyke could have received up to 20 years in prison for second-degree murder and up to 30 years for each of the 16 counts of aggravated battery – one count for each shot he fired at McDonald.

Cook County Circuit Court Judge Vincent Gaughan did not sentence Van Dyke for the aggravated battery conviction, explaining that second-degree murder was the more serious crime. Van Dyke is appealing the conviction.

Monday’s move is the latest chapter in an ongoing saga that has included massive demonstrations, the firing of the police superintendent by the mayor and the ouster of the county’s top prosecutors by voters a few months later.

The guilty verdict issued by a jury in October marked the first time an on-duty Chicago police officer was convicted for the killing of a black person.

A spokeswoman for Van Dyke’s lawyer did not immediately respond to the Associated Press new agency’s request for comment.